Bump nokogiri from 1.10.7 to 1.10.8 in /examples/simple_rails_api

Bumps [nokogiri](https://github.com/sparklemotion/nokogiri) from 1.10.7 to 1.10.8.
- [Release notes](https://github.com/sparklemotion/nokogiri/releases)
- [Changelog](https://github.com/sparklemotion/nokogiri/blob/master/CHANGELOG.md)
- [Commits](sparklemotion/nokogiri@v1.10.7...v1.10.8)

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

examples/simple_rails_api/Gemfile.lock

@@ -86,7 +86,7 @@ GEM
     minitest (5.13.0)
     msgpack (1.3.1)
     nio4r (2.5.2)
-    nokogiri (1.10.7)
+    nokogiri (1.10.8)
       mini_portile2 (~> 2.4.0)
     puma (4.3.1)
       nio4r (~> 2.0)